1. Field of the Invention
This invention relates to the field of security systems for monitoring restricted areas, such as in and around a vehicle, and provides more features, greater range of operator-system interface, and more user-friendly operation than those systems in the prior art. More particularly, this invention provides for multiplexing sensor output signals to a single wire for feeding and coupling to the alarm system.
2. Description of the Prior Art
Electronic security systems have been in use for many years monitoring or controlling access to secured or restricted areas. These security systems normally use several sensors or trigger devices for monitoring an area of restriction. A central controller monitors these devices and takes the appropriate action upon receipt of an input from one or more sensors. Examples of such security systems would include vehicle and home or business security systems. In today's art a radio frequency pulse-width-modulated remote-control transmitter controls many of these security systems. The pulse-modulated radio frequency remote-control transmitter signal is digitally encoded to match the coding of the central controller's decoder, thereby restricting access of the security system to the allotted operators.
Security systems are no longer just security systems, but personal convenience systems as well. Vehicle security systems today offer the operator many new, advanced features that were not even considered a few years ago. Today the radio frequency remote-controlled vehicle security system provides remote door locking/unlocking, remote trunk release, remote window roll up/down, and remote vehicle starting, to mention a few of the newer features.
Most remote-controlled security systems today use both an audible and a visual arm/disarm notification signal to verify arming and disarming of the security system. On many occasions, this would be considered a nuisance because it could disturb people in an apartment complex, in a parking garage, or any residence when someone arrives late at night. Most vehicle security systems today have some method of permanently disabling siren chirps (audible notification signals), but this does not give the user the flexibility of choosing when to generate audible notification signals. A few security systems accomplish this by a radio frequency remote-control transmitter, but those lose something in the process. One such system delays the chirps (remote RF signal confirmation) until a second input on the control channel is received or not received (the arm/disarm notification is just delayed). Another uses a second remote channel to disable the chirps, but loses use of that channel for other purposes.
As of today no known security system uses a light sensor to control the vehicle's light systems. There are light sensor products for vehicles on the market, but none are built into a security system. Some use a light sensor to turn on lights, others turn on lights when the wipers are turned on, and some use a light sensor in vehicle convenience systems.
Most security systems with input diagnostic and bypass capabilities allow as many as 10 full alarm trips, triggered by one input, before disabling that input. If the security system's remote-control transmitter resets an alarm cycle, the input is re-enabled; and there is no timer to re-enable the input if the input stabilizes or the environment changes. With today's sensors and the high sensitivity at which the user wishes them to operate, it is not uncommon for a sensor to develop some periods of instability, particularly with changes in the environmental conditions. Most of todays security systems do not allow a sensor back into the system once it has been disabled until the security system is disarmed and rearmed.
In present-day security systems, a "hidden" switch may be manipulated by the owner to turn off the security system and allow the remote-control transmitter to be used only to lock and unlock the doors. This is called the "valet" mode and is used for vehicle servicing, etc. Valet mode is a set condition of the security system in which the operator may have control of convenience features, but all alarm functions and outputs are disabled.
One of the convenience features of today's remote security systems is the capability to add a remote car starter. This allows operators in extreme cold climate areas to remote-start their vehicles to prevent engine block freezing, and to start their vehicles in the morning to warm the vehicle. During hot periods, operators may pre-cool their vehicles before they get in to drive. Usually when a vehicle is started by remote control, the security system must be disabled in some manner, otherwise the vibrations, voltage surges, and movement of the vehicle, would activate the alarm.
The programming of operational functions on most of today's security systems is accomplished through switches, jumpers, and input/output selection. This means the user or installer, if required, must access the control module to change any of the operational functions of the security system. This is a nuisance in that most times the control module is buried under the dash, under a seat, or behind a kick panel. This limitation of the user interface with the system is a major problem with today's security systems.
The testing of one of today's complex security system's installation can be a long and tedious task. The installer must check all the inputs to make sure that they are properly connected. He or she must also check all of the outputs to verify that they operate properly. They also must check that the security system has proper range for the RF remote-control transmitter. One existing system has a built-in test mode, which is referred to as a "real time zone monitoring diagnostic mode" and a "RF performance mode". However, in these cases the installer requires assistance on the inside of the vehicle to monitor the LED or speaker. Other security systems have to be continually armed and disarmed while these tests are conducted. This is a tedious task, but it also could be damaging to the security system or vehicle since each time a security system is armed or disarmed the doors are locked or unlocked, the lights flash, and the siren chirps.
As stated in previous patents, one way an intruder gains access to a secured area is to remove and restore power to the security system, which on many older security systems will leave the security system inactive. Most of todays security systems will restore to full alarm mode when power is reapplied, unless a certain condition is preset before power is restored.
The audible chirps or synthesized voice signals of today's security system are quite loud in a low-noise environment, which can be a nuisance under many situations. These audible signals are always of the same intensity day or night, in a busy parking lot, in a hospital zone, etc. Some security systems have the capability to completely silence these audible signals, but none have the capability to reduce the volume of these audible signals within the control module.
Another drawback to the alarms of the prior art is the multiplicity of wires required for coupling of sensors to the alarm controller. It is customary to have at least one wire connecting a sensor and the alarm control system.
In prior art applications, a wire harness and/or pathway was a part of every design. By the time all the wires are routed to a single location, the wires encumber a significant space requirement contributing to the failure rate of the alarm system, its complexity, added cost, and installation complexity. This invention provides for single wire reception of all sensor outputs wherein all the sensor outputs are multiplexed into a wire pair leading to the system controller.
The present device carries the capability of coding each sensor with a specific pulsewidth, thus allowing the controller to identify the source of alarm initiation and cataloging the occurrences of the same.